1. Field of the Invention
The present invention relates to an image-forming apparatus such as a display apparatus using an electron beam, and a method of manufacturing the same.
2. Related Background Art
Conventionally, as an image-forming apparatus using electron-emitting devices, a plane type electron beam display panel is known in which an electron source substrate with a number of cold cathode devices formed thereon and an anode substrate provided with anode electrodes and phosphors are opposed to each other in parallel, and an inside thereof is exhausted to a vacuum. For example, U.S. Pat. No. 5,066,883 and the like disclose such an image-forming apparatus using surface conduction electron-emitting devices. A plane type electron beam display panel using surface conduction electron-emitting devices can be rendered light-weight and have a large screen, compared with a cathode ray tube (CRT) that is widely used at the present. Such a plane type electron beam display panel can also provide a higher quality image with higher brightness, compared with other plane type display panels such as a plane type display panel using liquid crystal, a plasma display, and an electroluminescent display.
In a conventional plane type electron beam display panel as an exemplary image forming apparatus using electron-emitting devices, a vacuum container is composed of a rear plate, a face plate, and a side wall (supporting frame). Electron-emitting devices are provided on an electron source substrate of the rear plate, and phosphors and anode electrodes (metal back, etc.) are provided on the face plate, in such a manner that one phosphor corresponds to one electron-emitting device. Furthermore, the electron-emitting devices are connected to row-directional wirings and column-directional wirings. In the electron beam display panel with the above-mentioned structure, in order to accelerate electrons emitted from an electron source, a high voltage (Va) of about hundreds of V to several kV or more is applied between the rear plate and the face plate. The brightness of the image-forming apparatus substantially depends upon Va, so that it is required to increase Va in order to obtain high brightness. However, when Va is increased, discharge may occur in the image-forming apparatus. Particularly, in the case where spacer members are disposed in the image-forming apparatus for the purpose of keeping a predetermined interval between the rear plate and the face plate and of supporting the plates against an atmospheric pressure, and in the case where getter members are disposed for the purpose of maintaining a high vacuum state, an electric field is likely to be concentrated in the vicinity of these spacer members and getter members, which may cause discharge.
Furthermore, in the structure in which a supporting frame is disposed in the vicinity of anode electrodes so as to miniaturize the image-forming apparatus, surface creepage may occur via the surface of the supporting frame.
The above-mentioned discharge suddenly occurs during an image display, which may not only disturb an image but also remarkably degrade the electron source in the vicinity of a discharge portion. Accordingly, there is a possibility that a display may not be conducted normally.